1. Field of the Invention
The present invention relates to a simulation model creating method, a mask data creating method and a semiconductor device manufacturing method.
2. Related Art
In recent years, with the micronization of LSI, the OPE (Optical Proximity Effect) which causes dimension fluctuations and shape changes between the pattern of the mask used in the exposure and the pattern obtained on the wafer has become a problem. For this reason, OPC (Optical Proximity Correction) in which the mask pattern is corrected by taking into account the OPE in advance has been adopted (see, for example, L. W. Liebmann, B. Grenon, M. Lavin, S. Schomody, and T. Zell, “Optical proximity correction, a first at manufacturability,” Proceedings of SPIE Vol. 2322 (1994), pp. 229-238).
One OPC technique which allows a high level of correction accuracy to be obtained is model-based OPC by which suitable amounts of adjustment for mask dimensions are computed based on a lithography simulation is known. In model-based OPC, various parameters of the lithography simulation are found from OPE characteristics, such as line dimension pitch-dependency, obtained in advance by experiment (i.e. the OPE characteristics are modeled).
One experiment used to acquire the OPE characteristics involves forming a test pattern on a wafer and measuring dimensions of the pattern using a CD-SEM (Critical Dimension-Scanning Electron Microscope).
The measurement results of the pattern dimensions can include abnormal values caused by autofocus errors and the like. However, conventionally, the model is created with the abnormal values still included, causing the problem of a drop in modeling accuracy.